Double casing with netting for food products and production method therefor

ABSTRACT

A casing is embodied as a hollow stiff cylindrical support provided with an attachment mechanism in its coupling to the stuffing horn, on which is placed a suitably shirred tube which in turn is coated with a separation sheet and finally by a tubular net, also compressed or shirred, and which together with the inner tube extends beyond the support tube and is clamped against the tube by a clip, staple or knot such that during the stuffing operation the shirred tube and the equally shirred net are axially extended, with a simultaneous yet independent extension of the two elements favored with the aid of the intermediate separation sheet.

BACKGROUND OF THE INVENTION

The invention relates to a double casing for food products, comprised ofa flexible tube of an edible or inedible material, shirred, that isexternally coated with a length equivalent to the amount of the tube ofa tubular net, elastic, semi-elastic or non-elastic disposed coaxiallyto the tube and compressed or shirred in the same extent as the tube isshirred, so that it occupies an equivalent length.

The beginning of the compressed or shirred tubular net is slightlydisplaced from the beginning of the shirred tube, so that a fewcentimeters of the latter are not coated. Between the shirred tube andthe compressed tubular net can be provided a cylindrical separationsheet made of any material, such as a plastic film.

The above described assembly can be internally supported by a hollowcylinder made of a stiff material.

The above system, continuously or discontinuously and by way of asimultaneous unshirring of the film and the net, can provide a doublewrapping formed by the overlapping film and the tubular net that thatcan be filled by closing the film and the net jointly on the open endand stuffing inside a solid or semisolid product with a stuffing hornplaced inside the support tube of the assembly.

The area of shirred film not coated by the compressed or shirred tubularnet ensures that the latter will not prevent the shirred film fromunfolding easily because of the compression force exerted on it. As thefilm and the net are unshirred to form the casing, the front ends of theshirred film and net move back in the same extent, so that there isalways an area of uncoated and free shirred film. The separation sheetallows the film to become unshirred uniformly and ensures that theportion of shirred film that is not coated by the compressed net is notcarried away by the latter as it unfolds.

The product described can be used for manual or automatic packaging offood products that may or may not be later subjected to any processes ofdrying, maturing, curing, cooking, sterilization, etc., in which thefilm casing and outer net assembly are required.

The invention also relates to the method for manufacturing said product.

The use of double casings for meat products, and specifically thoseexternally including string, mesh or nets has been traditionallyemployed for several purposes, among which are the following:

1)As a decorative mechanism in order to give the product an externalappearance with a greater finish in some cases, or more traditional andartisan-like in others. In other cases, the object is to ensure that thefinished product maintains the characteristic mark made by the net afterthe casing is removed.

2)As an additional compression system for the first casing, so that airis eliminated more effectively to obtain an improved appearance andconservation of the products, or to hold tightly the stuffed productduring the cooking process in order to achieve a proper bonding of themeat. For products undergoing a drying process, the mesh, string or nethelp the tripe remain joined to the surface of the product despite theshrinkage resulting from the drying process.

3)As a system for holding the inner casing so that the entire stuffedpiece maintains a uniform gauge. This is important for casings made ofplastic, collagen or regenerated cellulose of large caliber with atendency for their diameter to vary. Coating these pieces withsemi-elastic or non-elastic nets helps solve this problem.

4)As a system for hanging the products, whether for their heat treatmentin cooking ovens or for a drying process. The external coating ofstring, mesh or net provides, in addition to a basic hanging system, aneffective support for the weight of the product which in many caseskeeps the casing from breaking.

Traditionally, this second external casing is placed manually as anadditional operation after the first casing is stuffed. This operationhas always been labor-intensive.

One of the first improvements of the traditional method is described inU.S. Pat. No. 1,505,218 (Sartore, 1924) and consists of a double casingcomprising an inner cylindrical tube coated by a cylindrical net. Thisdouble casing is cut into segments of a length matching that of a pieceof the final product to be stuffed. The advantages provided over thetraditional method is to give the internal piece a greater resistance,so that it can be stuffed at a higher pressure, thereby eliminating theair more efficiently and reducing the number of breakages, but aboveall, reducing the time required to place the net after stuffing with theensuing savings in labor costs.

A second improvement is described in U.S. Pat. No. 5,024,041 (Urban,1991), which describes a method where both the inner casing and theouter net are shirred, the former on the stuffing tube of a stuffingmachine and the latter on a tube concentric to the aforementioned onehaving a large enough inner diameter, so that with the two closed by astaple or clip it is possible to perform the stuffing continuously andautomatically. This invention also incorporates a retainer brake for thefirst casing. In addition to these advantages the system also allows afaster stuffing operation.

U.S. Pat. No. 5,980,374 (Mercuri, 1999) provides an additionalimprovement, and consists of a double casing comprising an inner tubularcasing and an outer elastic cylindrical net placed concentrically toeach other and later shirred jointly. The advantage is that bothcomponents form a single piece and can be used as a traditional simplecasing, placing them on the stuffing horn without requiring additionaltubes to place the net, and further preventing the need to load saidnet.

Although all of the aforementioned inventions constitute importantimprovements of the system, there remain a few significant aspects toresolve. The system disclosed by U.S. Pat. No. 5,024,041 (Urban, 1991),although providing a continuous stuffing method, requires an additionaltube to support the net and a system for attaching said tube to thestuffing machine. Additionally, the net must be loaded on this tube in aseparate operation, with the corresponding additional time and laborcosts. Furthermore, each time the inner casing or net is finished, whichare not always simultaneous, it is necessary to stop the operation toreplace the exhausted supply. This also slows down the system andincreases labor costs.

The system described in U.S. Pat. No. 5,980,374 (Mercuri, 1999),although solving some of the aforementioned problems, such as the needfor accessories to support the net, and somewhat reducing the number ofstoppages for placing either the inner casing or the net, as theirlength is substantially the same in each unit of double shirred casing,this approach has a disadvantage in that said length is limited becauseof the joint shirring of the two components. Thus, in the shirred stick,the length of double casing contained in each fold is at most thedistance between the elastic transversal threads of the net, as duringthe shirring operation and as described in the corresponding patent, theelastic transversal threads are placed spontaneously at the troughs ofthe folds, thereby limiting the length of the double casing contained ineach one. In addition, the number of folds per unit length contained inthe stick depends on the thickness of each fold, that is, the sum of thethickness of the inner casing and the thickness of the elastic thread.

SUMMARY OF THE INVENTION

All of these disadvantages are satisfactorily solved by the presentinvention, the objects of which are summarized as follows.

In view of the above discussion, it is an object of the invention toprovide a double casing for food products comprised of a flexible innertube and an outer net, both shirred independently and placed coaxially,ready to be used, allowing a simultaneous application of the flexibletube and the net to any product, preferably a food product, stuffedinside it.

Also the object of the invention is to provide a system that renders itunnecessary to place accessories for supporting the nets in the stuffingmachines, that prevents the costly operation of loading the net in saidaccessories and additional stoppages in order to replace the twodifferent packaging elements, the cylindrical casing and the net, whichare not always exhausted at the same time, thereby reducing the cost ofthe operation. As a corollary, it can be added that the system isapplicable to any stuffing machine.

A further object of the invention is to provide a double casing that cancontain larger amounts of tube and net in considerably shorter lengthsof shirred product stick than in traditional systems, by virtue of thecoaxial arrangement of the tube and the net, allowing an independent andmore compact shirring thereof.

Yet another object of the invention is to facilitate the jointunshirring of the tube and the net during the use of the double casingby placing a separation sheet between them.

Lastly, another object of the invention is to prevent the externallyshirred net from hindering the unshirring of the inner tube by placingthe former farther back than the latter.

DESCRIPTION OF THE DRAWINGS

As a complement of the description being made and in order to aid abetter understanding of the characteristics of the invention, accordingto an example of a preferred embodiment, an accompanying set of drawingsis provided as an integral part of the description where for purposes ofillustration only and in a non-limiting sense the following is shown:

FIG. 1 is a schematic perspective representation of a tube for wrappingfood products, made of an edible or inedible material, shirred on ahollow support cylinder made of a stiff material;

FIG. 2 is a perspective view similar to the previous figure of the sameassembly after the separation sheet has been incorporated;

FIG. 3 is another perspective view similar to those of the previousfigures, after incorporating the external net;

FIG. 4 is a schematic side elevation and sectional view of the assemblyof the previous figure; and

FIG. 5 is a schematic side view of a machine used to place the net.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The figures are provided only for purposes of illustrating preferredembodiments of invention, the scope of which includes other arrangementsor designs of both the tube, the nets and the protection sheets and/orhollow support cylinders.

FIGS. 1-4 illustrate embodiments of the invention that are showncomprising a support tube 1 made of a stiff material having anattachment mechanism 2 securing it to the stuffing horn, on which isplaced a suitably shirred tube 3 with this assembly being coated with aseparation sheet 4 and finally with a tubular net 5, also suitablycompressed or shirred, and that together with the inner tube 3 extendsbeyond the support tube 1 and is strangled against it by a clip, knot orstaple 7.

The support tube 1 is a stiff tube made of any material, preferably onesuitable for being in contact with food products. Its length, innerdiameter and wall thickness can vary according to the width of the tube,the characteristics of the net, the length of the stuffing horn of themachine used to fill it, the total length of the tube and net to beshirred and compressed, etc.

The stuffing horn on which the system is placed will determine theminimum inner diameter of the hollow support cylinder, so that theformer will fit inside the latter. The same is true of its length, asthe stuffing horn must always be longer than the hollow support cylinderfor the tube. The thickness of the wall of the hollow support cylinderwill mainly depend on its strength, and should be enough to withstand,without deformation, the pressure transmitted by the net, particularlywhen the net is elastic. The hollow support cylinder can have anyattachment mechanism to the stuffing horn and can be perforated to allowwetting the inner shirred tube before it is used whenever this isnecessary.

The tube 3 can be made of an edible or inedible material, preferably onesuitable for being in contact with food products, shirred in anaccordion-like manner to form folds perpendicular only to itslongitudinal axis, or also parallel to said axis, in order to containthe greatest possible length in a minimal space.

In order to allow the air that is trapped when stuffing the product toexit during the heat treatment, the tube can be previously perforated.The size and distribution of the orifices can be variable and shouldallow air to exit, yet ensure retention of fluids and the mechanicalstrength of the tube.

The separation sheet 4 for the shirred tube 3 and the net 6 that islater placed can be made of any material, preferably one suited to comein contact with food products; its purpose is to separate the shirredtube from the compressed net so that when the two are simultaneouslydeployed, the friction and drag of the film by the net is prevented, sothat the deployment is uniform and the tube is not damaged by the net.It can consist of an enveloping sheet with the edges glued to form atube, or can be formed as a tube directly, or can be a simple envelopingsheet suitably overlapped. This sheet is attached to the hollow supportcylinder on the rear to prevent the sheet from being carried away by thenet when the latter is extended. It can be attached to the tube by anadhesive or by any other suitable method.

Finally, the net 5 comprises a sock or tube-shaped weave with walls madeof threads, fibers or string of vegetable-origin materials such ascotton and/or latex, synthetic materials or a mixture thereof, suitablyintertwined to form a characteristic weave. The most common netscomprise an elastic thread coated with a cotton or synthetic fiber,arranged in a spiral along the entire length of the sock or tube, withadjacent coils attached to each other by threads knotted at regularintervals forming a grid closed onto itself in which the transversefibers are elastic and the longitudinal ones are not. There are alsosemi-elastic nets in which the weave has a certain degree of elasticity,as well as non-elastic nets. In the latter case the threads candetermine a great variety of weaves, forming diamonds, hexagons, etc.

The net 5 is compressed similarly to the shirring of the inner tube 3for non-elastic and semi-elastic nets; however, for elastic nets, theelastic coils of the spiral that form the transverse rings of the netare arranged concentrically as shown in FIG. 4, remaining by theirelasticity such that unshirring can take place smoothly, so that the netthat is still compressed or shirred will not press against the net thatis being deployed at any time, as at all times and because of the mannerin which the double casing is prepared, which is also part of the scopeof the invention and that will be described further below, the order ofcompression or shirring of the net is opposite to that of decompressionor unshirring, that is, the last portion of net deployed is the first tobe compressed. This system allows compressing or shirring a great lengthof tubular net in a small space.

The assembly formed by the compressed net, which comprises a length ofnet substantially equal to that of the shirred tube, is placed a fewcentimeters behind 6 the assembly of the shirred tube (FIG. 3). Thereason for this is so that the front of the film is never pressed on bythe net and is thus free to be unshirred during the stuffing operation.As the assembly is extended both fronts, that of the shirred tube andthat of the compressed net, are retracted in parallel and keep thissafety distance 6 at all times.

The assembly can incorporate a clip, knot or staple on its open end, asa closure, so that it is not necessary to perform this operation at thestart of the stuffing operation.

In order to manufacture the described product, in its most developedversion, a commercially available cylindrical hollow stick of flexibleshirred tube 3 made by any known method is used, inside which is placeda hollow support cylinder 1. After this assembly is coated with theseparation sheet 4 the net is placed and shirred, by a machine as thatshown in FIG. 5.

Specifically, in this machine, a coil of net 8 is placed in thecoil-bearing system 9 of the machine and a certain length of net isunwound, making it pass through a tensioning roller 10 and thenthreading it in the rear end of a floating spindle 12 until it is placedunder the carrier wheels 13 of the net.

Then the stick of the shirred cylindrical tube 3 is mounted on thehollow cylindrical support 1 and is placed after it is coated with theseparation sheet 4 on the support 14 for the stick retraction system 15,and the latter is placed inside the hollow floating spindle 12 until theend of the shirred film is inserted a few centimeters in the spindle.

Afterwards the carrier wheels 13 and the stick retraction system 15 areset in motion so that the net falls on the stick as the latter retracts,coating it with an amount of net equivalent in length to that of thepreviously shirred film. The density of the net shirred in this mannerwill be determined by the speeds of the carrier wheels 15 and theretraction system 15.

EXAMPLES

In order to define the scope and characteristics of the invention, thefollowing examples are provided as illustrating preferred embodiments,and not to limit the scope of the invention.

Example 1

Two sticks with a double tube and net casing were manufactured, oneaccording to the system described in the description of the preferredembodiments, which is referred to as the “independent coaxialarrangement” of the tube and net sticks, and the other by shirringjointly and simultaneously the tube and the net to form a single stick.The relevant data of the materials used and the dimensions of the sticksproduced are shown below in the following table:

TABLE 1 Independent coaxial Joint arrangement arrangement Externaldiameter of the hollow 53 mm 53 mm support cylinder Diameter of theinner tube-casing 70 mm 70 mm Thickness of the inner tube-casing 0.0875mm 0.0875 mm Inner tube-casing material Fibrous Fibrous Separation sheetPolyethylene — 0.04 mm Gauge of the latex thread of the net 0.9 mm 0.9mm Distance between net coils 15 mm 15 mm Type of latex/polyesterelastic net 12 spaces/5 knots 12 spaces/5 knots Total length of doublecasing stick 430 mm 430 mm Total meters shirred 30 m 6 m Shirring ratio:casing length/stick 69.76 13.95 length

Table 1 shows that the stick manufactured according to the systemdescribed a preferred embodiment has 30 meters of double casing ascompared to the 6 meters contained in the one manufactured with thejoint shirring method, both on 430 mm of stick, that is, 5 times more.The shirring ratios are respectively 69.76 and 13.95 meters of doublecasing per meter of stick.

Example 2

Two sticks with a double tube and net casing were manufactured, oneaccording to the system described in the description of the preferredembodiments, which is referred to as the “independent coaxialarrangement” of the tube and net sticks, and the other by shirringjointly and simultaneously the tube and the net to form a single stick.The relevant data of the materials used and the dimensions of the sticksproduced are shown below in the following table:

TABLE 2 Independent coaxial arrangement Joint arrangement Externaldiameter of the 63 mm 63 mm hollow support cylinder Diameter of theinner tube- 80 mm 80 mm casing Thickness of the inner tube- 0.0875 mm0.0875 mm casing Inner tube-casing material Collagen Collagen Separationsheet Polyethylene — 0.04 mm Gauge of the latex thread of 0.7 mm 0.7 mmthe net Distance between net coils 8 mm 8 mm Type of latex/polyester 14spaces/3 knots 14 spaces/3 knots elastic net Total length of double 500mm 500 mm casing stick Total meters shirred 25 m 7.12 m Shirring ratio:casing 50 14.24 length/stick length

Table 2 shows that the stick manufactured according to the systemdescribed in the invention has 25 meters of double casing as compared tothe 7.12 meters contained in the one manufactured with the jointshirring method, both on 500 mm of stick, that is, 3.5 times more. Theshirring ratios are respectively 50 and 14.24 meters of double casingper meter of stick.

Example 3

Two sticks with a double tube and net casing were manufactured, oneaccording to the system described in the description of the preferredembodiments, which is referred to as the “independent coaxialarrangement” of the tube and net sticks, and the other by shirringjointly and simultaneously the tube and the net to form a single stick.The relevant data of the materials used and the dimensions of the sticksproduced are shown below in the following table:

TABLE 3 Independent coaxial arrangement Joint arrangement Externaldiameter of the 63 mm 63 mm hollow support cylinder Diameter of theinner tube- 90 mm 90 mm casing Thickness of the inner 0.05 mm 0.05 mmtube-casing Inner tube-casing material Polyamide Polyamide Separationsheet Polyethylene — 0.04 mm Gauge of the latex thread 0.7 mm 0.7 mm ofthe net Distance between net coils 8 mm 8 mm Type of latex/polyester 14spaces/3 knots 14 spaces/3 knots elastic net Total length of double 270mm 430 mm casing stick Total meters shirred 16 m 6.6 m Shirring ratio:casing 59.26 15.34 length/stick length

The table shows that the stick manufactured according to the systemdescribed in the description of the preferred embodiments has 16 metersof double casing as compared to the 6.6 meters contained in the onemanufactured with the joint shirring method, the first on 270 mm ofstick and the second on 430 mm of stick, that is, almost 4 times moredouble casing per unit length of stick in the independent coaxialarrangement. The shirring ratios are respectively 69.76 meters and 13.95meters of double casing per meter of stick.

For the purposes of promoting an understanding of the principles of theinvention, reference has been made to the preferred embodimentsillustrated in the drawings, and specific language has been used todescribe these embodiments. However, no limitation of the scope of theinvention is intended by this specific language, and the inventionshould be construed to encompass all embodiments that would normallyoccur to one of ordinary skill in the art.

The particular implementations shown and described herein areillustrative examples of the invention and are not intended to otherwiselimit the scope of the invention in any way. For the sake of brevity,conventional aspects of the systems (and components of the individualoperating components of the systems) may not be described in detail.Furthermore, the connecting lines, or connectors shown in the variousfigures presented are intended to represent exemplary functionalrelationships and/or physical or logical couplings between the variouselements. It should be noted that many alternative or additionalfunctional relationships, physical connections or logical connectionsmay be present in a practical device. Moreover, no item or component isessential to the practice of the invention unless the element isspecifically described as “essential” or “critical”. Numerousmodifications and adaptations will be readily apparent to those skilledin this art without departing from the spirit and scope of the presentinvention.

1. A double casing for food products, comprising: a tube of an edible orinedible material; and an elastic, semi-elastic or non-elastic tubularnet, the tube and the net both being shirred independently and placedcoaxially, the tube being coated externally by the net which is shirredto a same extent as the tube so that it occupies an equivalent length.2. The double casing for food products, according to claim 1, whereinthe tubular net is placed farther back than the tube.
 3. The doublecasing for food products according to claim 1, further comprising acylindrical separation sheet made of any material that is placed betweenthe shirred tube and the net.
 4. The double casing for food productsaccording to claim 1, further comprising an internal support for theshirred tube, said internal support being made of a hollow supportcylinder of a stiff material.
 5. The double casing for food productsaccording to claim 4, further comprising attachment mechanism of thehollow support cylinder for attachment to a stuffing horn.
 6. The doublecasing for food products according to claim 4, wherein the hollowsupport cylinder is perforated.
 7. The double casing for food productsaccording to claim 1, wherein the material of the tube is ediblecollagen of bovine or porcine origin.
 8. The double casing for foodproducts according to claim 1, wherein the material of the tube isinedible collagen.
 9. The double casing for food products according toclaim 1, wherein the material of the tube is regenerated collagen. 10.The double casing for food products according to claim 1, wherein thematerial of the tube is regenerated or fibrous collagen.
 11. The doublecasing for food products according to claim 1, wherein the material ofthe tube is a plastic material.
 12. The double casing for food productsaccording to claim 1, wherein the material of the tube is hemp paper.13. The double casing for food products according to claim 1, whereinthe material of the tube is any type of paper.
 14. The double casing forfood products according to claim 1, wherein the material of the tube isa polysaccharide.
 15. The double casing for food products according toclaim 1, wherein the material of the tube comprises a combination ofmaterials selected from the group consisting of edible collagen ofbovine or porcine origin, inedible collagen, regenerated collagen,regenerated or fibrous collagen, a plastic material, hemp paper, anytype of paper, and a polysaccharide.
 16. The double casing for foodproducts according to claim 1, further comprising a coloring pigment ormixture of pigments added to the material of the tube, continuously ordiscontinuously, to form a drawing, stripes, letters, numbers or anyother design.
 17. The double casing for food products according to claim1, further comprising an aromatic substance added to the material of thetube.
 18. The double casing for food products according to claim 1,further comprising a plastic substance added to the material of thetube.
 19. The double casing for food products according to claim 1,wherein the tube is perforated in order to allow its aeration.
 20. Thedouble casing for food products according to claim 1, further comprisinga clip, staple, or other attachment mechanism for holding one of theends of the double casing.